Yea I love my ob 120 with classic that's wht I use now as main player I just got offred a deal on a mezz with the wd700 was jw what everyone thought of them
Mezz makes awesome stuff. there's no questioning that. If your happy with your setup now, and playing well with it, I wouldn't change.
Think of your cue like golf clubs. Sure next year's models might be a LITTLE better, but you will have to adjust your game for how those clubs play. Same thing with different cues. If you dedicated to the adjustment for your new gear, go for it.
WD700 i can't speak for. Never played one. I'm not a big fan of laminated shafts in general to be honest. That being said, if I was going to buy and LD shaft for my cue it would be nothing but OB. Those guys build an amazing product for the money.
I've never played a Mezz cue, or shaft in my life so i could be completely off basis.Out of all the LD shafts I played, I like the OB classic pro the best.
My opinion is entirely based upon the handful of interactions I've had with OB Cues. Whether on this site, through helping friends with warranty issues, and calling them up on the phone. From what I have read and seen about Mezz, they are top notch, but I wouldn't personally know.
Not a lot of help above, but you have a good cue now. I wouldn't go looking to change, just for the sake of change.